Glass substrates have been used as substrates for Liquid Crystal displays (LCD). The Glass substrate has very good performance. However, it encounters more and more limitations in latest applications, because it is rigid, not flexible, easily broken and difficult for manufacturing thinner panel, and in addition cost is high.
A flexible plastic substrate is introduced to resolve these problems. However, current available sealant materials can not be used for flexible plastic substrate LCD panel assembly due to too big difference between plastic and glass substrates, especially in terms of thermal expansion property and cure temperature restriction.
Therefore, there has been a great demand fora new type sealant technology having good reliability performance and suited for the flexible plastic substrate.
Attempts of lowering the curing temperature have been carried out in the past, but the results are still not satisfactory. In patent document 1 (WO2001/098411; JP-B-4358505), thermal curability at 80° C. was reached but it is two-component composition, difficult to be handled in real panel assembly process. For compositions disclosed in patent document 2 (JP-A-2001-174099; JP-B-3968208) and patent document 3 (JP-A-2001-142086; JP-B-3920511), cure temperature of at least 110° C. is necessary, which is still high for most flexible plastic substrates. In addition, flexibility of these proposed compositions was not satisfactory enough.